Benchmark: Push with if vs Map with filter

Script Preparation code:

var strs = Array.from(new Array(10000)).map(() => 'String concat. ')
var result = []

Tests:

Push with if
for (let i = 0; i < strs.length; i++) { if (i % 2 === 0){ result.push(strs[i]) } }
map with filter
result = strs.map((a) => a).filter((a) => a % 2 === 0)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Push with if
map with filter

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 123 on Android

View result in a separate tab

Test name	Executions per second
Push with if	872.4 Ops/sec
map with filter	1769.5 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

I'll break down the benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmark that compares two approaches to push elements onto an array: using a traditional `for` loop with an `if` statement (`Push with if`) versus using the `map()` and `filter()` methods (`Map with filter`).

**Script Preparation Code**

The script preparation code initializes two arrays:

1. `strs`: An array of 10,000 strings, each containing the string "String concat ".
2. The result array `result` is initialized as an empty array.

**Html Preparation Code**

There is no HTML preparation code provided.

**Individual Test Cases**

There are two test cases:

### Push with if

This test case uses a traditional `for` loop to iterate over the `strs` array and push elements onto the `result` array. The loop condition checks if the current index `i` is even using the modulo operator (`%`). If it is, the string from `strs` is pushed onto `result`.

```javascript
for (let i = 0; i < strs.length; i++) {
  if (i % 2 === 0) {
    result.push(strs[i]);
  }
}
```

### Map with filter

This test case uses the `map()` and `filter()` methods to achieve the same result in a more concise way. The `map()` method applies a function to each element of the array, returning a new array with the results. In this case, the function simply returns the original string. The `filter()` method then removes any elements that don't meet the condition (i.e., even indices).

```javascript
result = strs.map((a) => a).filter((a) => a % 2 === 0);
```

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

### Push with if

Pros:

* Easy to understand and implement, especially for those familiar with traditional `for` loops.
* Can be optimized using techniques like loop unrolling or caching.

Cons:

* May have performance overhead due to the need to check the index condition in each iteration.
* More verbose than the `map()` and `filter()` approach.

### Map with filter

Pros:

* More concise and expressive, making it easier to read and maintain.
* Can be optimized using techniques like memoization or caching.

Cons:

* May require more understanding of functional programming concepts.
* Can have performance overhead due to the creation of intermediate arrays.

**Library: Lodash**

The `filter()` method uses the built-in JavaScript `Array.prototype.filter()` method, which is a part of the ECMAScript standard. However, in some cases, additional libraries like Lodash may be used to provide an implementation for the `filter()` method on older browsers or platforms that don't support it natively.

In this benchmark, it's unlikely that Lodash would be used explicitly, as the `Array.prototype.filter()` method is widely supported.

**Special JavaScript Feature: No explicit mention**

There are no special JavaScript features or syntaxes being tested in this benchmark. The focus is on comparing two approaches to push elements onto an array using standard JavaScript methods.

**Other Alternatives**

If you're looking for alternatives to push elements onto an array, here are a few options:

1. `concat()`: This method appends one or more arrays (or values) to the end of another array.
2. Spreading (`...`): You can use the spread operator (`...`) to expand an array into multiple arguments to a function.
3. `Array.prototype.reduce()`: This method reduces an array by applying a function to each element, accumulating the result.

Keep in mind that these alternatives may have different performance characteristics and trade-offs compared to using `push()`.

Related benchmarks:

Push with if vs Map with filter (version: 0)

Comparing performance of: Push with if vs map with filter

Created: one year ago by: Guest

Jump to the latest result

Push with if

map with filter

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):